将计划设置为活动后，您将无法更新该计划.限制的原因是因为可能基于该计划达成协议，因此对其进行修改会影响已经达成协议的结算协议.

You cannot update the plan, once it is set to active. The reason for that restriction is that because there could be possible agreements based on that plan, modifying it would affect the already agreed billing agreements.

但是，我同意您的问题说明，更改返回URL不应成为问题，因为这不是协议的一部分，而是更多的配置更改.即使启用后，也可以通过某种方式允许在Plan中更新类似的设置，这将是很好的.我会让API小组知道这一点.

However, I agree with your problem statement, that changing the Return URL should not be an issue as this is not a part of agreement, but more of a configuration change. It would be nice to somehow allow updating similar settings in Plan, even after active. I will let the API team know about that.

但是，与此同时，您将无法做到这一点.或者，您可以创建一个新计划，然后使用它.不是您要寻找的答案，而是可能的解决方案.

however, in the mean time, there is no way you would be able to do that. Alternatively, you could possibly create a new plan, and use that instead. Not the answer you are looking for, but a probable solution.